THE SEED BANK DYNAMICS OF TWO DIFFERENT FOREST TYPES IN SOUTHERN SRI LANKA

Abstract

The floristic composition and regeneration potential of natural forests in wet zone(Wilpita) and dry zone (Hambanthota) was investigated by sampling in the top IOcm ofthe soil using special desigri samples (30cm*30cm* lOcm) along the transects andenumerating the number of seedlings emerge from the soil during the period of twomonths. The seedlings were transferred into poly bags once a week and allowed to grow forfew months to determine the floristic composition.

The mean number of seeds germinated per square meter in Wilpita in Hambanthota were162 and 146 respectively. The composition of the seedlings from Wilpita and Hambanthotaforests was not similar, though the population density was generally higher in the Wilpitaforests. The floristic composition at the Wilpita forests was observed and Alstoniamacrophy/a (Hawarinuga), Macaranga Pe/teta (Kande), Trema orienta/is (Gedumba) andMelastoma malabathricum (Bovitiya) were prominent species among the tree species.Affinity analysis showed that the Alstonia was the most prominent tree species in Wilpitaforest There was no significant difference observed in the number of seedlings per squaremeter among the samples collected along tbe transects.

This study shows that the regeneration potential of the rain forests in the wet zone(Wilpita) is much higher than forests in the dry zone.